The U.S. patent of Bonanni, No. 4,818,058, granted Apr. 4, 1989, incorporated herein by reference, describes an optical fiber connector comprising a pair of support members on opposite sides of an array of parallel optical fibers. The support members are made of monocrystalline silicon into which matching V -grooves, for holding the fibers, have been formed by photolithographic masking and etching. The sides of the support members define reference surfaces against which bear a pair of alignment pins. The pins allow the connector to be precisely abutted to another identical connector to splice together two arrays of optical fibers, i.e., to abut each optical fiber with a fiber of the other array with sufficient precision to allow optical energy to flow relatively unimpeded through the interconnection. The Bonanni device is successful because of the great precision with which V-grooves can be defined in monocrystalline silicon.
The reference surfaces on the sides of each support member are defined by etching to a significantly deeper depth than the etching used to define the fiber-supporting V-grooves. Although the Bonanni patent says that it may be possible to make the reference surfaces simultaneously with the fiber V-grooves, the specifications for most optical fiber connectors make such simultaneous etching impractical; instead, the reference surfaces must be made by a masking and etching step which is separate from the etching step used to make the fiber V-grooves. This in turn requires a high degree of alignment of the reference surface features with the fiber V-groove features. This requirement has been found to reduce the yield of optical fiber connectors since, in some cases, the masks defining the reference surfaces are sufficiently misaligned with respect to the V-grooves as to make the support member unusable. That is, if the reference surfaces are misaligned too much with respect to the fiber V-grooves, the alignment pins will be misaligned with respect to the optical fibers, and the accuracy of abutment needed for successful splicing as described above will not be met.
Consequently, there is a long-felt need in the industry for a method for making optical fiber connectors in which the reference surfaces are in precise predetermined registration with respect to the fiber-supporting V-grooves. There is a further need that this be accomplished in a way that does not require extraordinary cost or exceptionally high skill on the part of the workers using the method.